This Megalodon jaw reconstruction here, very well-done by the way, as well as a host of other well-reconstructed extinct species discovered from the area, including this Gomphotherium, are to be found at the Museo de Naturaleza y Arqueologia de Calakmul, Calakmul, Campeche, MX. Susan and I literally stumbled upon this extremely well-done little museum in the middle of the Mayan jungle isolated from any other towns on our honeymoon ten years ago. Calakmul, a biosphere reserve now, is the name of the newly discovered ancient Mayan city that once existed here. It would have been about 7.7 square miles in area with 6,250 structures discovered so far! The base of the great pyramid covers almost 5 acres, making it the largest Mayan construction in existence and while we were there it was actively being explored by researchers! It is a UNESCO World Heritage Site and you can read more here for a good general introduction to this incredible recent archeological discovery.
https://www.worldheritagesite.org/list/Calakmul
https://natpacker.com/destination/calakmul-biosphere-reserve/